> Another way to think about SHA2 and SHA3 is that it's entirely possible that SHA3 could fall before SHA2 does. They are unrelated algorithms.
Very good point, though I would expect SHA2 to see far more research on weakening it. It's been around a lot longer, and its wider deployment makes it a much higher value target. (Is SHA-3 supported anywhere right now?)
You can easily make the converse point and claim that SHA2 has a higher probability to resist future cryptanalysis than SHA3, given that SHA2 has already had a lot more research than SHA3, but is still not broken. "Old" is a feature in this sense. The only issue I know about with SHA2 is its length extension property. And that is by design.
